This invention relates to fully formulated detergent compositions comprising a mixture of one or more detersive surfactants and a zwitterionic tetramethylene oxide (TMO) compound. More particularly, this invention encompasses detergent compositions comprising mixtures of one or more detersive surfactants with novel zwitterionic co-surfactants characterized by a particular placement and number of TMO groups and particular hydrophobic groups. The combination of these ingredients provides superior detergency performance over a broad spectrum of soils and with a wide variety of fabric types.
The use of zwitterionic compounds (i.e., the so-called "internally neutralized" surface active compounds having both positive and negative charge centers) in fully formulated laundry detergent compositions is known. In contrast with many prior art detergents, the compositions herein employ zwitterionic compounds having a TMO substituent which provides both charge separation and hydration interposed between the oppositely-charged centers of the molecule as a co-surfactant. The TMO-zwitterionics are particularly useful for removing clay and oily soils from fabrics.
The importance of the present invention resides not only in the superior cleaning performance of the disclosed compositions, but also in the flexibility in the choice of surfactants and the favorable economics of the compositions. For example, the TMO moiety can be introduced into the instant zwitterionic co-surfactants using tetrahydrofuran as a precursor. Tetrahydrofuran, in turn, is available from plant by-products such as corncobs, oat hulls, cottonseed hulls, and bagasse. To this extent, the TMO-based zwitterionics are not based on scarce petrochemical feedstocks in the manner of ethylene oxide-containing surfactants. Nonetheless, the zwitterionic compounds used herein are somewhat expensive, relative to many "ordinary" detersive surfactants. By the practice of this invention, the TMO-zwitterionics can be blended with less expensive surfactants to provide compositions which exhibit superior cleaning performance at lower cost than compositions containing the TMO-zwitterionic as the sole surfactant, Moreover, desired suds levels, specialized cleaning uses, etc., can be provided by proper variations of the detersive surfactant. Finally, the optional use of builders in combination with the surfactant/TMO-zwitterionic co-surfactant mixtures herein allows the formulation of superior detergents for both fabric and hard surface cleaning at the most economical cost.